[19a-E315-1~11] 13.9 Compound solar cells

△ [19a-E315-9] The Effect of a Buffer Layer on a CuGaS₂ Thin Film Solar Cell's Performance

〇Myeongok Kim¹, Nazmul Ahsan², Li Kao Zacharie Yehl⁴, Logu Thirumalaisamy², Kalainathan Sivaperuman⁵, Yoshitaka Okada^2,3 (1.Grad. Arts and Sci. UTokyo, 2.RCAST UTokyo, 3.Elec. Eng. UTokyo, 4.IREC, 5.VIT)

Keywords:CuGaS2 solar cell, chemical bath deposition, buffer layer

Optimal buffer layer on CuGaS₂ (CGS) is a prerequisite for its potential application to intermediate band CGS solar cells. This research, therefore, compares the solar cell performances of CGS solar cells (CGS-SCs) with CdS and CdZnS buffer layers deposited by chemical bath deposition. It is found that CGS-SC characteristics are improved with CdZnS buffer layer, especially at short wavelength region. It is speculated to be due to the band widening effect of Zinc doping on the buffer layer. The band gap of CdS is comparable to that of CGS, affecting the light absorption and carrier collection. However, a widened buffer layer makes it transparent to short wavelength photons, and the loss at the buffer layer with its poor crystallinity is suppressed.